<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <style>
        div {
            width: 100px;
            height: 100px;
            background: blue;
            transition: width 2s;
            -moz-transition: width 2s; /* Firefox 4 */
            -webkit-transition: width 2s; /* Safari and Chrome */
            -o-transition: width 2s; /* Opera */
            display: none;
        }
        p{
            color: #cccccc;
            font-size: 30px;
        }
    </style>
    <script src=lib/jquery/jquery.min.js></script>
</head>
<body>
<p>klajf</p>
<div id="div"></div>
<button id="ii">点击</button>
<script>
    var div = $('#div');
    $("#btn").click(function () {
        div.css('display','block');
    });
</script>
</body>
</html>
